Continuous-strip anode for magnetrons



April 10, 1951 N. P. NICHOLS 2,548,808

CONTINUOUS-STRIP ANODE FOR MAGNETRONS Filed Nov. 6, 1945 FIG.4

FIG.5 .7

FIG. 6

. INVENTOR.

NATHAN P NICHOLS 2 LL Q.

ATTORNEY Patented Apr. 10, 1951 CONTINUOUS-STRIP ANODE FOR MAGNETRONS Nathan P. Nichols, Danvers, Mass, assignor, by mesne assignments, to the United States of America as represented by the Secretary of War Application November 6, 1945, Serial No. 627,038

4 Claims.

My invention relates in general to electrical apparatus and more particularly to apparatus for the generation of oscillatory electromagnetic energy.

One method of generating an oscillatory electromagnetic wave is by means of a magnetron oscillator. From such an oscillator, waves of extremely short wavelength and high power may be obtained. Such oscillators find employement in various type of communication systems including pulsed radio object locating systems.

Heretofore, magnetrons have embodied a cathode electrode surrounded by an anode electrode consisting of a block of conducting material chambered with a plurality of individual cavity resonators. The construction of such an anode block requires a high degree of precision in manufacturing technique since each block must be machined individually to close tolerances. In many cases the conformation and location of the cavity resonators is such as to render their manufacture extremely dilficult.

Accordingly, it is one object of my invention to provide a new type of magnetron oscillator anode.

Another object of my invention is to provide a magnetron anode structure which permits of easy manufacture.

Still another object is to provide a magnetron anode structure which may be fabricated without machining.

These and further objects of my invention will be apparent to those skilled in the art to which the invention belongs.

Briefly, my invention comprises a method of forming cavity resonators individually or in multiple from a relatively thin sheet or ribbon of conducting material and assembling the resonators to form a complete magnetron oscillator tube. My invention will best be understood by reference to the drawings in which:

Fig. 1 shows a unit cavity resonator formed according to the principles of my invention;

Fig. 2 shows a magnetron oscillator employing cavity resonators of the type shown in Fig. 1;

Fig. 3 shows a series of cavity resonators which are formed simultaneously;

Fig. 4 shows a magnetron oscillator employing the resonators of Fig. 3;

Fig. 5 shows a series of resonators of differing sizes which may be formed simultaneously; and

Fig. 6 shows a magnetron oscillator employing the resonators of Fig. 5.

Referring to Fig. 1 there is illustrated a ribbon 5 of suitable conductive material which may be bent by means of a simple jig or stamping device into a shape approximately that of a horse shoe, thereby creating a cavity having definite resonant characteristics. There may be provided tabs such as 6 and I which are formed integrally with the ribbon and these may be utilized to hold the cavity in place when a number of these cavities are assembled for the purpose of providing a plural cavity magnetron, for instance. Well known means may be used to cooperate with the tabs, and accordingly, forms of retaining structures are not illustrated herein.

Referring to Fig. 2 there is shown schematically a magnetron oscillator utilizing cavity resonators of the type hereinbefore illustrated in Fig. 1. In this figure a retaining ring Ill embraces a number of the individual cavity resonator units such as illustrated in Fig. 1, the units being placed in a radial fashion around a center aperture into which may be inserted the normal operating cathode of the tube. In actual practice strapping ring might be provided to hold the individual units as well as for the other purposes for which strapping rings are adaptable.

Referring to Fig. 3 there is illustrated an arrangement showing the product which may be formed from a continuous ribbon-like strip of conducting material. Since this is purely schematic, no thickness has been attached to the ribbon other than that of the thickness of a normal line in the drawing. In this case a continuous ribbon I2 is pressed to form a succession of U-shaped members which are arranged adjacent each to the other. It will be apparent that these may easily be arranged around a common axis in a desired fashion to form a multi-cavity set of resonators. In the complete assembly the ends would be brazed together.

Referring to Fig. 4 there is shown schematically a magnetron oscillator employing the resonators formed as shown in Fig. 3. In this case the ends of the U-shaped members are forced inwardly toward each other so that the cavity resonators are formed around a center axis. The ends of the resonator cavities may be held by strapping rings (not shown) which serve not only to hold the resonant cavities but perform the functions normally attributable to strapping rings. "Strapping rings may be brazed in place together with the resonator cavities. The anode ring I 5 of the magnetron then embraces the collection of resonant cavities.

Referring to Fig. 5 there is illustrated one way of forming a series of cavity resonators of differing sizes from a continuous strip I! of ribbonlike conductive material. This may be formed by well-known means, and accordingly the exact method of manufacture need not be illustrated here.

Referring to Fig. 6 there is shown schematically a magnetron oscillator employing the resonators formed in accordance with the teachings of Fig. 5. In this figure the anode ring i9 may be placed around the cavities which have been forced together so as to be disposed radially around a center point. A proper aperture for the insertion of the cathode in the magnetron is left and in general the cathode forms the axis about which the resonators are disposed; With this arrangement strapping is not absolutely required. Again the thickness of the ribbon I! has not been taken into consideration While there have been illustrated preferred embodiments of my invention, it will be appreciated that there may be deviations therefrom which still will follow within the spirit of the invention, and accordingly I claim all such modifications as fall fairly within the'spirit and scope of the hereinafter appended claims.

What I claim is:

1. An electrode for a magnetron discharge device comprising a cylindrical metal retaining ring forming part of the vacuum envelope and a multi-cavity resonator supported from the inner surface of the ring having polar vanelike extremities projecting inwardly toward the retaining ring axis, said multi-cavity resonator being formed from a continuous ribbon-like metal strip pressed into a succession of cylindraceous U-shaped members open at the ends constituting resonators arranged adjacent to each other symmetrically around the retaining ring axis.

2. An electrode for a magnetron discharge device comprising a cylindrical retaining ring forming part of the vacuum envelope and a multi-cavity resonator supported from the inner surface of the retaining ring with the polar extremities of the resonators projecting inwardly toward the retaining rin axis, said multi-cavity resonator being formed from a continuous ribbon-like metal strip pressed into a succession of adjacent cylindraceous U-shaped members open at the ends each member constituting a cavity resonator, the rounded portion of each U member being adjacent to the inner surface of the retaining ring and the polar extremities projecting inwardly toward a common axis.

3. An electrode for a magnetron discharge device comprising, a cylindrical retaining ring and a multi-cavity resonator arranged symmetrically around the inner surface of the ring, said multi-cavity resonator comprising a continuous. strip of ribbon metal bent to form a plurality of integral U-shaped cavities said strip being bent into a circular form with the open ends of the Us projecting inwardly toward a common axis and set as a unit within said retaining ring.

4. An electrode for a magnetron discharge device comprising a cylindrical retaining ring and a multi-cavity resonator arranged symmetrically around the inner surface of the ri said multi-cavity resonator bein formed from a continuous ribbon-like metal strip pressed into a succession of cylindraceous U-shaped convolutions open at the ends constituting cavity resonators, the adjacent sides of the U elements forming vane-like polar members projecting inwardly toward a central recess coaxial with said retaining ring.

NATHAN P. NICHOLS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,802,185 Read Apr. 21, 1931- 2,123,728 Hollmann July 12, 1938 2,128,237 Dallenbach Aug. 30, 1938 2,217,745 Hansell Oct. 15, 1940 2,247,077 Blewett et al June 24, 1941 2,348,986 Linder May 16, 1944 2,406,277 Bondley Aug. 20, 1946 2,417,789 Spencer Mar. 18, 1947 2,432,608 Desch et al Dec. 16, 1947 

